The influence of environmental factors on Juniperus seedling growth and mortality in Juniperus woodlands and their role in community replacement or succession is poorly understood. A full factorial field experiment was set up to investigate the influence of adult tree canopies, light levels and water and nutrient additions on Juniperus ashei seedling growth and mortality. Relative growth rates calculated from basal diameter, height and number of seedling branches were used as response variables in a four- way multivariate analysis of variance, using canopy, light levels, water and nutrient manipulations as factors. The pattern of seedling growth in the experiment was best explained with two significant three- way interactions between the canopy, light level and water treatments (F = 2.21, P = 0.04) and light level, water and nutrient treatments (F = 3.01, P = 0.03). Greatest seedling relative growth rates occurred with modified light levels associated with canopies removed, with supplemental water and nutrients. Mortality was increased by shading with supplemental water, added nutrients or a combination of supplemental water and nutrients. Conversely, mortality was not affected by canopy treatment, but it was reduced with high light levels, the additions of nutrients, water or combinations of nutrients and water. Evidence suggests that growth of J. ashei seedlings and eventual replacement of the adults is most strongly influenced by light levels, and at higher light levels, both water and nutrients interact to support continued growth.